Timing of actions represents a fundamental factor for many aspects of human behavior. LEE, “Sensory and intrinsic coordination of movement,” Royal Soc. of London, 2029-2035 (1999). In tennis, as well as in other sports or vocational activities involving coordination of complex movements or actions, timing is essential to the smooth flow of performance during a game or activity. The timing encompasses broad aspects of the activity. For example in tennis, timing is involved in game elements ranging from court motion, posture and stance, and attention allocation, to stroke preparation and execution (see LANDLINGER, “Key factors and timing patterns in the tennis forehand of different skill levels,” J. Sports Sci. & Med., 9(4):643 (2010), which provides an investigation of key kinematic features and their timing in forehand strokes).
Execution of properly timed actions relies heavily on perceptual processes that provide the cues necessary for planning and timing of these actions. This action-perception cycle is a dynamic system (see KUGLER, Information, natural law, and the self-assembly of rhythmic movement. Hillsdale, N.J.: Erlbaum Associates, (1987) and WARREN “The dynamics of perception an action.” Psychological review 113.2 (2006): 358.).
Moreover, this system forms an interactive process that can encompass the behavior of multiple actors and their interaction with their environment and task elements. In tennis for example, timing of actions, and plans of future actions are adapted continuously based on the outcome of those actions in the task or activity environment, and the adversary's reaction to one's own actions. Similar challenges are also present in cooperative situations such as the behavior of another team member in an operating room, where safe and efficient workflow requires the surgical team members to be able to correctly anticipate the timing and type of future actions.
Timing is a dynamic dimension that should be adapted to the continuous changes in an activity to achieve effective sequences of coordinated actions (e.g., court and stroke motions in tennis). Acquiring the skills to properly coordinate these processes is one of the most fundamental challenges for learning and performing in interactive multi-actor sports or similar activities.
Complex human movements involve the coordination of many degrees of freedom (muscles and joints) and often unfold too fast to be amenable to continuous feedback. Many activities involve action selection and implementation within fraction of a second, and proper execution requires synchronization down to milliseconds in some activities (BERNARDI et al. “Mental practice promotes motor anticipation: evidence from skilled music performance.” Frontiers in human neuroscience 7 (2013)). For example, a high-performance tennis stroke requires efficient transfer of momentum to the ball via the kinematic chain going from the legs, hip, core, to upper body and arms, and finally, the racquet. This entire chain of movements is implemented as a pattern and unit of movement for that particular stroke.
Therefore, these complex human movements cannot be produced instantaneously but rather rely on learned motion patterns. Once learned, these patterns are stored in procedural memory and act as units of organization for larger motion behaviors and interactions with the environment or other subjects or actors (see, BERNSTEIN, “The co-ordination and regulation of movement,” Pergamon, N.Y. (1967)).
Timing of these patterns plays a critical role in performance. Since the movement patterns are not instantaneous but of finite durations, their successful execution requires anticipation of the future actors' behavior and interactions in a particular activity. Therefore, their execution relies on the identification of cues that support the selection of the appropriate behavior pattern and the timing necessary for proper execution. In other words, effective performance in activities involving complex interactions with environments and other actors relies on a spatio-temporal structure that supports the coordination of events and facilitates advanced planning and organization.
For example, in tennis the players rely on characteristic patterns of play to extract anticipatory cues that help predict the future ball trajectory and player behavior. This information is then used to select and start the execution of the appropriate court and stroke movements. With adequate court positioning, posture, and stroke, the player can then optimally execute the associated units of movements.
Timing, preparation, and initiation of the tennis stroke and supporting units of movement, such as court positioning, are based on cues extracted from the environment which encompasses court and game events, such as the impact of the ball on the ground, as well as cues extracted from the adversary's behavior such as the adversary's stroke and racket-ball contact. These cues make it possible to predict the future ball trajectory and pattern of play in the adversary's game plan.
For tennis, the timing information about an adversary's return is one of the most basic cue, since up to the instant of impact it is difficult to predict the adversary's intended stroke placement on the court and the ball's pace and effect (i.e. spin). The impact therefore represents a primary focus of attention. The impact's strength and direction provides information useful for the prediction of the ball's trajectory which in turn is used to plan and initiate the sequence of stroke selection, preparations, and necessary body posture and court positioning.
Studies investigating tennis player's visual attention, however, have shown that advanced players are able to utilize early cues including the opponent's body stance, stroke preparation and initiation, while beginners tend to use later cues such as the oncoming ball's trajectory. ABERNATHY, “Expertise and the perception of kinematic and situational probability information,” PERCEPTION—LONDON—, 30(2):233-252 (2001). WILLIAMS, “Anticipation skill in a real-world task: measurement, training, and transfer in tennis,” J. of Exp. Psych: Appl., 8(4):259 (2002).
Beginners therefore are mostly challenged by the large amount of information available in a task environment. Advanced actors are able to filter through this information on the most relevant cues, but still can be prone to stress, distraction and effects of fatigue.
Humans and other animals can use a broad range of sensing and perception abilities, including the auditory and visual systems, to extract cues necessary to achieve effective planning and timing of actions. From the standpoint of ecological psychology some of these cues are readily available from the subject's direct perceptual experience of the environment interaction (GIBSON, The Ecological Approach to Visual Perception: Classic Edition. Psychology Press, 2014.).
Perceptual mechanisms in complex tasks depend on various cognitive mechanisms in particular attention (POSNER, “Orienting of attention.” Quarterly Journal of Experimental Psychology 32, no. 1 (1980): 3-25). Cueing therefore can help by focusing attention on relevant events in a task environment. In tennis, for example, a cueing system can be used to enhance attention to the major court events and relevant aspect of an adversary's behavior. A rudimentary behavioral aid used by some players is counting from 1 to 3. A player would count “1” at the adversary's ball contact, “2” at the bounce of the ball in the court, and “3” when striking the ball. This technique ostensibly supports the organization and coordination of the player's perceptual and motor processes.
What is needed are tools that help actors or players maintain timing and/or focus attention in interactive vocational performance and sports.